Question No. 01: What is gross
error?
Answer: These errors are mainly
due to human mistakes in reading or in using instruments or error in recording
observations. This error also occurs due to incorrect adjustment of instruments
and computational mistakes these errors cannot treat mathematically.
Question No. 02: What is the
function of Attenuator in CRO?
Answer: The voltage in input
terminal of the vertical amplifier causes the beam to deflect off the CRT
screen, is unite low in amplitude. So that high amplitude signals may be
displayed, an attenuator network is placed between the vertical input terminals
of the vertical amplifier. The main function of the attenuator is to reduce the
amplitude of the vertical input signal before applying it to vertical
amplifier.
Question No. 03: What are the basic
components of a CRO?
Answer: CRO Circuit consists of
following components:
- Vertical deflection system
- Horizontal deflection system
- Synchronization circuit
- Blanking circuit
- Intensity modulation
- Position control
- Focus control
- Cathode ray tube
- Calibration circuit
Question No. 04: What do you mean by
a Voltage transformer?
Answer: The transformers used
for voltage measurement are called voltage or potential transformer.
Question No. 05: What do you mean by
Turns ratio of instrument transformer?
Answer: It is the ratio of
number of turns in secondary winding to the number of turns in primary winding
of an instrument transformer.
Question No. 06: What are the three
major categories of error?
Answer: Error may arise from
different sources and are usually classified as:
- Gross error
- Systematic error
- Random error
Question No. 07: What is
measurement?
Answer: The process of
determining the amount, degree, or capacity by comparison (direct or indirect)
with the accepted standards of the system units being used.
Question No. 08: What is the
function of probe in CRO?
Answer: The probe performs the
very important function of connecting the test circuit to oscilloscope without
altering, loading or otherwise disturbing the test circuit.
Question No. 09: Which device is
used for the source of emission of electrons in a CRT?
Answer: A barium and strontium
oxide coated cathode is used for the source of emission of electrons in a CRT.
Question No. 10: What is the
function of electron-gun used in CRT?
Answer: The source of focused
and accelerated electrons beam is the electron gun. The electron gun emits
electrons and forms them into a beam consist of a heater, a cathode, a grid, a
pre-accelerating anode, a focusing anode and an accelerating anode.
Question No. 11: What do you mean by
a phase Angel of instrument transformer?
Answer: The angle between
secondary current and primary current of a current transformer is called phase
angle of instrument transformer.
Question No. 01: What do you mean by
ratio correction factor of instrument transformer?
Answer: It is the ratio of the
transformation ratio to the nominal ratio of an instrument transformer.
Question No. 12: What is accuracy of
a measurement?
Answer: The degree of exactness
(closeness) of a measurement compared to the expected (desired) value.
Question No. 13: Why Systematic
errors occur?
Answer: These error occur due to
- Instrumental error
- Environmental error
- Observational error
Question No. 14: What are the
functions of different probes used in CRO?
Answer:
Direct Probe: direct probe avoids stay-pick
up which may create problems when low level signals are being measured. It is used
for low frequency or low impedance circuit. Isolation probe: Isolation probe is
used in order to avoid the undesirable circuit loading effects of the shielded
probe.
Detector probe: when analyzing the
response to modulated signals used in Communications equipment like AM, FM and TV
receivers, the detector probe functions to separate the low frequency
modulation component from the high frequency carrier.
Question No. 15: What do you mean by
a Current transformer?
Answer: The transformers which
are used for measurement of current is called current transformer.
Question No. 16: What do you mean by
Nominal ratio of instrument transformer?
Answer: It is the ratio of rated
primary winding current to the rated secondary winding current of an instrument
transformer.
Question No. 17: What is Resolution
of a measurement?
Answer: The smallest change in a
measured variable to which an instrument will respond.
Question No. 18: What are the
reasons of instrumental error?
Answer: The instrumental errors
arise due to three main reasons:
- Due to inherent shortcoming in the instrument
- Due to misuse of the instruments
- Due to loading effect of instrument
Question No. 19: What is the
function of electron-gun assembly used in CRT?
Answer: The electron gun
assembly produces a sharply focused beam of electrons which are accelerated to
high velocity .this focused beam of electrons strikes the fluorescent screen
with sufficient energy to cause a luminous spot on the screen.
Question No. 20: What do you mean by
transformation ratio of instrument transformer?
Answer: It is the ratio of
primary winding current to the secondary winding current of an instrument transformer.
Question No. 21: What is precision
of a measurement?
Answer: A measure of the
consistency or repeatability of measurement, i.e. successive reading do not
differ.
Question No. 22: How many types of
probe used in CRO?
Answer: There are three types of
probe used in CRO:
- Direct probe
- Isolation probe
- Detector probe
Question No. 23: What is Error of a
measurement?
Answer: The deviation of the
change in output (response) of the instrument to a change of input or measured
variable.
Question No. 24: What are the types
of instrument transformer?
Answer: There are two types of
instrument transformer:
- Current transformer
- Voltage transformer
Question No. 25: What is Sensitivity
of a measurement?
Answer: The ratio of the change
in output (response) of the instrument to a change of input or measured
variable.
Question No. 26: What do you mean by
an instrument transformer?
Answer: Transformer which is
used with measuring instrument is called instrument transformers. Instrument
transformer is used as a protection circuit of power system for the operation
of over current, under voltage, Earth fault etc.
Question No. 27: What is Cathode ray
oscilloscope (CRO)?
Answer: Cathode ray oscilloscope
is an instrument used for display, measurement and analysis of waveforms and
other phenomenon in electrical and electronic circuit.
Question No. 28: What are the
Advantages of instrument transformer?
Answer: Advantages of instrument
transformer are:
- Instrument transformers are moderate in size and used for 5 A current and 100 to 200 V measurements.
- Instruments using instrument transformer are low cost.
- Replacement of damage parts is Easy.
- The metering circuit is isolated the high voltage power circuit hence insulation and safety is assured for operation.
- There is low power consumption in metering circuit.
Question No. 29: What is the
function of aquadag in a CRO?
Answer: An aquadag is used
in a CRO to collect secondary emission electrons.